Exlar Corporation 1470 Lake Drive West Chanhassen, MN 55317 www.exlar.com Tel: 952-368-3434 Fax: 952-368-4359
Mechanical Lifespan and Electrical MTBF Linear Products The travel life of an FT or GSM/X series linear actuator is determined by the life of the thrust bearings and the rotary to linear conversion device. In the GSMX series this is an inverted planetary roller screw. In the FT series this is a planetary roller screw. The estimated life of both components is determined using an L10 life calculation. The modified lifespan or Ln is calculated using a reliability factor, fr. These reliability factors are shown in table 1. Table 1 Reliability % 90 95 96 97 98 99
fr 1 0.62 0.53 0.44 0.33 0.21
The typically accepted nominal life span, L10, is calculated using fr = 1, at which point the survival probability is 90%. The nominal life span of a non-preloaded planetary roller screw is calculated using the following formula: L10 = (C/Fm)3 * 106 revolutions, where C is the dynamic load rating of the roller screw, and Fm is the cubic mean axial load applied to the screw in the application. This life can be converted to linear distance by multiplying L10 in revolutions by the lead of the roller screw. This life can be converted to hours by Lh = L10/(nm*60), where nm = the cubic mean speed of the roller screw in rev/min.
Exlar Corporation 1470 Lake Drive West Chanhassen, MN 55317 www.exlar.com Tel: 952-368-3434 Fax: 952-368-4359
Each roller screw also has a maximum static load rating which is a critical loading point, which cannot be exceeded in the application with out damage to the components. Table 2 shows the dynamic and static load rating for the GSM/X and FT series roller screws. Table 2 Actuator Size GSX20
GSXX30 GSX40
GSX50
GSX60
FT35
FT60
FT80
Screw Lead (in) 0.1 in 0.2 in 0.4 in 0.2 in 0.5 in 0.2 in 0.5 in 0.8 in 0.1 in 0.2 in 0.5 in 1.0 in 0.25 in 0.5 in 1.0 in 5 mm 10 mm 20 mm 6 mm 12 mm 30 mm 6 mm 12 mm 30 mm
Cdynamic (lbf)
Cstatic (lbf)
Actuato r Size
Cdynamic (lbf)
Cstatic (lbf)
2,075 1,540 1,230 5,800 4,900 8,300 7,030 6,335 15,693 13,197 11,656 6,363 25,300 22,800 21,200 10,700 8,650 7,080 51,900 44,500 41,600 80,400 70,100 64,700
2,090 2,050 1,970 6,300 6,500 9,600 9,900 10,200 31,100 30,700 30,100 27,000 52,600 50,200 48,000 17,100 17,700 17,800 91,500 98,200 99,100 142,000 158,000 182,000
GSM20
1245 924 738 3,570 3,016 4,890 4,218 3,328
1,380 1,305 1,270 3,880 3,910 5,550 5,800 5,150
GSM30 GSM40
The GSX series of linear actuators uses a single back to back set of angular contact thrust bearings. The FT series of linear actuators uses a duplex set back to back angular contact thrust bearings. The nominal life span of a tandem set of angular contact thrust bearings is calculated using the following formula: L10 = (C/Fm)3 * 106 revolutions, where C is the effective dynamic load rating of the thrust bearings, and Fm is the cubic mean axial load applied to the bearings in the application. This life can be converted to hours by Lh = L10/(nm*60), where nm = the cubic mean speed of the bearings in rev/min. All of the above data assumes a properly installed, maintained and lubricated device.
Exlar Corporation 1470 Lake Drive West Chanhassen, MN 55317 www.exlar.com Tel: 952-368-3434 Fax: 952-368-4359
Each bearing set also has a maximum static load rating which is a critical loading point, which can not be exceeded in the application with out damage to the components. Table 3 shows the effective dynamic and static load ratings for the GSX/M and FT thrust bearing configuration applicable for each actuator series and size. Table 3 Actuator Size GSX/M20 GSX/M30 GSX/M40 GSX50 GSX60 FT35 FT60 FT80
Cdynamic (lbf) 9,588 19,380 26,000 42,000 59,670 32,334 105,400 162,180
Cstatic (lbf) 7,803 15,861 23,900 44,700 63,410 23,698 91,800 162,180
In determining the travel life of the actuator and the maximum static load, the lower of the Cdynamic or Cstatic for each combination of roller screw and bearings should be used. Seals and bushings are considered normal wear and maintenance items and are not considered in travel life evaluations. All of the above data assumes a properly installed, maintained and lubricated device. Rotary Products The mechanical lifespan of the SLM and SLG products is determined by the loading of the bearings in the SLM and the bearings and the gears in the SLG products. The calculated mechanical life for each product is according to the data below. Radial Load Radial Load for 10,000 hour bearing life at 25mm from motor face RPM 50 100 250 500 Lbf (N) 195 (867) 155 (690) 114 (507) 90 (400) SLM/G060 Lbf (N) 389 (1730) 309 (1375 227 (1010) 180 (801) SLM/G090 Lbf (N) 939 (4177) 745 (3314) 549 (2442) 435 (1935) SLM/G115 Lbf(N) 1350 (6006) 1071 (4767) 789 (3512) 626 (2788) SLM142
1000 72 (320) 143 (636) 346 (1539) 497 (2213)
Exlar Corporation 1470 Lake Drive West Chanhassen, MN 55317 www.exlar.com Tel: 952-368-3434 Fax: 952-368-4359
Output Torque Ratings for 10,000 life, SLG Output Torque @ Speed for 10,000 Hour Life 1000 RPM 3000 RPM 5000 RPM lbf-in Nm lbf-in Nm lbf-in Nm 144 170 200 224 240 275 288 340 320 600 775 890 912 980 1250 1200 1550 1100 1392 1445 1660 2112 2240 2350 2800 2900 2500
(16.2) (19.2) (22.6) (25.3) (27.1) (31.1) (32.5) (38.4) (36.1) (67.8) (87.6) (100.6) (103.4) (110.7) (141.2) (135.6) (169.4) (124.3) (157.3) (163.3) (187.6) (238.6) (253.1) (265.5) (316.4) (327.7) (282.5)
104 125 140 160 170 200 208 245 280 456 590 680 688 740 950 920 1200 1100 1132 1175 1350 1714 1840 1900 2240 2350 2500
(11.7) (14.1) (15.8) (18.1) (19.2) (22.6) (23.5) (27.7) (31.6) (51.5) (66.7) (76.8) (77.7) (83.6) (107.3) (103.9) (135.6) (124.3) (127.9) (132.8) (152.6) (193.0) (207.9) (214.7) (253.1) (265.5) (282.5)
88 105 120 136 146 180 180 210 240 396 510 590 592 640 825 800 1000 1100 1000 1040 1200 1518 1620 1675 2000 2100 2400
(9.9) (11.9) (13.6) (15.4) (16.5) (20.3) (20.3) (23.7) (27.1) (44.7) (57.6) (66.7) (66.9) (72.3) (93.2) (90.4) (112.9) (124.3) (112.9) (117.5) (135.6) (171.0) (183.0) (189.2) (225.9) (237.3) (271.2)
Exlar Corporation 1470 Lake Drive West Chanhassen, MN 55317 www.exlar.com Tel: 952-368-3434 Fax: 952-368-4359
Output Torque
Model SLG060
SLG090
SLG115
Ratio 4:1 5:1 10:1 16:1 20:1 25:1 40:1 50:1 100:1 4:1 5:1 10:1 16:1 20:1 25:1 40:1 50:1 100:1 4:1 5:1 10:1 16:1 20:1 25:1 40:1 50:1 100:1
Maximum Allowable Output Torque Load (User Controlled) lbf-in Nm 603 (68.1) 522 (58.9) 327 (36.9) 603 (68.1) 603 (68.1) 522 (58.9) 603 (68.1) 522 (58.9) 327 (36.9) 2078 (234.8) 1798 (203.1) 1126 (127.2) 2078 (234.8) 2078 (234.8) 1798 (203.1) 2078 (234.8) 1978 (203.1) 1126 (127.2) 4696 (530.4) 4066 (459.4) 2545 (287.5) 4596 (530.4) 4696 (530.4) 4066 (459.4) 4696 (530.4) 4066 (459.4) 2545 (287.5)
Exlar Corporation 1470 Lake Drive West Chanhassen, MN 55317 www.exlar.com Tel: 952-368-3434 Fax: 952-368-4359
Electrical The FT series of linear actuators do not contain electrical components. MTBF data for motors mounted to FT series actuators can be obtained form the manufacturer of that motor. The electrical components contained within the GSX actuator are the brushless motor stator and the feedback device. Feedback Devices: Standard GSX actuators utilize frameless resolvers, quadrature encoders or absolute encoders as the primary rotary feedback device. These are purchased form outside sources and the manufacturer provides the MTBF data. Under normal operating conditions, at 25°C the average MTBF for the standard type resolvers used in Exlar products is approximately 992,000 hours and for encoders used in Exlar products is approximately 200,000 hrs. Exlar configures its products to use encoders and resolvers as specified by the amplifier manufacturer to whose product the Exlar product will be connected. The variations in these feedback devices is continuously being added to with feedback products from various manufacturers. Brushless Motors: Instantaneous MTBF for the brushless motors in the Exlar Products is 205,000 hrs.
